What were the main divisions in the French Revolution?
The French Revolution was characterized by a number of divisions, including between some of the major cities, especially Paris, and the countryside, which tended to be more radical, and between middle class liberals and radical sans-cullotes. This question seems to be addressing the social divisions at the beginning of the Revolution, however.
At the outbreak of the French Revolution, society was divided into three estates, or social orders, that were established both by custom and by law. While recent historians have established that there was much more mobility and mutuality of interest between the classes, especially the Second and Third Estates, they still remain useful in understanding the divisions and inequalities that characterized French society under the ancien regime. These inequalities contributed to the outbreak of the Revolution.
The First Estate consisted of the clergy, both the higher clergy, including bishops, who were drawn from noble families, and the lower clergy, made up of parish priests. The Second Estate, or the nobility, included the noblesse de robe, which was made up of royal officials, many of whom had purchased their positions, and the noblesse d'epee, most of which came from older noble families. The Third Estate included everyone else, from peasants to urban wage laborers. Its political voice, however, was largely drawn from the bourgeoisie, which included lawyers, merchants, and other wealthy, educated men.
Crucially, the French tax system privileged the first two estates, exempting them from most taxes, which fell most heavily on the Third Estate. These privileges made the nobility (or most of them, anyway) highly resistant to reform which created a situation that culminated with a intractable fiscal crisis in the late 1780s. The Third Estate, naturally, supported the abolition of these privileges, and when King Louis XVI summoned the Estates-General in an attempt to reform the antiquated system, it led to revolution.